SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5310d18cc91b788f2bcaf7f98b510d828364f3075ef57fb4ad32a053722c9b2e' 
  AND token = '3YGhAqwijSKZyYV4vlLpDUiYVWTUcZkd74g3V01Alqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}